This invention relates to a strainer for use in filtering and a method of manufacturing such a strainer of plastics. More specifically, a strainer of the type to which this invention relates, is the cylindrical one which is to be attached to the end of a suction pipe for removing impurities from the fuel in supplying from a gasoline tank.
A variety of such strainers have been hitherto proposed, and actually used. Same of these conventional strainers are composed of a metallic cylindrical frame having a metallic net applied to the whole cylindrical surface thereof. Others are composed of a plastic cylindrical frame having a plastic net embedded in and integrally connected to the body of the frame.
As for the strainer of the former type, applying a net around the frame body requires a tedious and time-consuming work, and therefore such metallic strainers cannot be produced at a low cost. As for the strainer of the latter type, the top and bottom plastic boards cannot be integrally connected to the opposite ends of the plastic cylindrical frame at the time of moulding. Because if the top and bottom boards were integrally connected to the opposite ends of the frame body in a mould die, these boards would prevent the moulded body from being removed from the mould die. In this connection the top and bottom boards are made separately from the cylindrical frame body, and later those boards are connected to the opposite ends of the cylindrical frame to constitute a closed body. Apparently, the separate moulding and subsequent connecting work are disadvantageous to massproduction.
One object of this invention is to provide a strainer which is free from the defects mentioned above.
Another object of this invention is to provide a method of making such strainers.